Chromic acid treatment of feathers



CHROMIC ACID TREATMENT OF FEATHERS Varsenig Z. Pasternak and Robert M. Lollar, Cincinnati, Ohio, assignors to the United States of America as represented by the Secretary of the Army No Drawing. Application April 23, 1957 Serial N0. 654,615

8 Claims. (Cl. 8-94.10),

This invention relates to a method of treating land fowl feathersQespecially chicken feathers, to increase their filling power and resiliency, and to impart permanent curliness and water repellency, thereby making such feathers an acceptable substitute for the standard down and feather mixture now in wide use for sleeping bags, comforters, etc. Another object is to provide a treatment which enables the feathers to retain much of their high filling power after several washings with a detergent. A further object is to employ a chemical treatment which will make the feathers resistant to moths. Other objects will be apparent from the following description of the method presently preferred by us.

In explanation of the term filling power,reference may be made to the report entitled A Proposed Method for Measuring the Filling Power of Down and Feathers by Henry A. Sinski, publication No. TD103037, The Ofiice of Technical Services, Department of Commerce, and to the article by N. B. Edelman in Textile Research Journal, vol. 17, p. 199 (April 1947), entitled Investigation of Methods for Determining the Filling Power of Feathers. Seealso the Sinski et al. Patent No.2,706,9l dated April 26, 1955. Ordinarily, chicken feathers have a filling power of 1.8 to 2.1 cm., while the 40/60 downfeather mixture has a filling'power of 5.3 to 5.9 cm. The term feathers as used herein includes whole land fowl feathers of the desired size rang crushed (commercial curled) land fowl feathers, land fowl feather fibers, stripped land fowl, feathers, and mixtures of these.

In the preferred procedure, the feathers, if not known to be entirely free from blood, are first soaked for about ten minutes in a water solution of a commercial blood solubilizer, such as "Coagusol" (a mixture of sodium hexametaphosphate and alcohol sulfate). After the soaking, the solution is drained from the feathers and the feathers are then laundered or dry cleaned. In laundering, preferably a detergent such as Tergitol NPX (alkyl phenyl ether of polyethylene glycol) is used- (0.25%,water solution at 110l2 F.).; Other nonionic detergents have been found to be satisfactory. In

general, the non-ionic type of detergentsshould be used to obviate any action on the protein of the feathers. Laundering continues for about twenty minutes, then the solution is removed from the feathers by centrifuging or wringing. While'a number of well-known dry cleaning perfectly clean, the. soaking and washing or'dry cleaning may be omitted.

If the feathers are from immature chickens, the damp feathers from the described laundering or dry cleaning operation are placed in a 1% water solution of trisodium phosphate Na PO .l2H O at 43-49 C. for about ten minutes. If feathers from mature chickens are being processed, the phosphate treatment period is increased to flitC SEQI patn 7 about thirty minutes. This mild the final feather product.

' hydrazine bath (6 g. of hydrazine sulfate plus 1300 g.;

feathers were kept in this reducing bath for fifty minutes.

for twenty-five minutes, dried and relaxed. The fillingv power reading"was'6.3"cn"1. 'After'beiiiglaundered 531d 'ice the feathers is believed to alter the stability of the feathers by modification of the cystine linkages in the keratin. This step is important because it materially increases the eurliness of the feathers, and it curls naturally uncurly mature feathers, thereby increasing the bulk value of Other suitably buffered alkaline solutions, for example, sodium carbonate or borax, may be used in lieu of the phosphate solution mentioned above, but in all cases the time of the treatment must be less for immature feathers to avoid excessive degradation.

the higher concentration of cystine linkages in mature feathers enables themto resist the action of the alkaline solution for a longer period. The data from successful laboratory'runs at The Tanners Council Research Laboratory, University of ;Cincinnati will now be given. a

Bromoacetic acid-Chromic acid -Hydrazine treatment A bath of 45 grams of chicken feathers was first treated with trisodium phosphate as described above. The feathers were removed from the bath and thoroughly rinsed with water, then they were treated witha 5% bromoacetic acid solution (56 g. bromoacetic acid in 900 ml. water) which was neutralized to pH 7 by the addition of ml. of 10% Na CO solution. After fifteen minutes, the pH wa'sraised to 9 9.5 and the feathers were kept in the bath for 4 /2 hours at 48 5l C, Then the feathers were removed and thoroughly rinsed. Next the feathers were placed in a chromic acid bath (1000 ml. of 0.8% chromic acid or 1% sodium bichromate of pH 2.5-2.7) and kept there for 2% hours at 34-44 C.

Then the feathers were transferred to a bath of 1000 ml.- of 0.1% hydrazine solution and kept there at 379-3130;

Chloroacetic acid-kChromic acid-l-Hydrazine treatment A batch of 67 grams of chicken feathers was first given the described phosphate treatment, then was rinsed for twenty minutes. of 1500 ml. of 2.4% chloroacetic acid (monochloroacetic acid) for twenty minutes at pH 2.9 and 42 C. Next sodium carbonate solution was added to raise thepH," and the feathers were kept in the sodiumchloroacetic acid solution for two hours at pH 9.2-9.4, temperature. 41 -47 C. Then thefeathers were well rinsed and were immersed in a chromic acid bath (15g. sodium bichro-j mate in 1500 ml. ofwater plus 2 mlfof concentrated sulfuric acid) to two hours at '4145 C., the pH being 2.52.7. The next step was to transfer the feathers to a of water plus 200 g. of mother liquor, which was spent chromic acid solution; i.e., chromic acid solution left over from the chromic acid bathdescribed in the preceding sentence, after removal of the feathers therefrom). The

at pH 4.2, temperature 3842 C. Therrthe pH was raised to 6.8, the temperature remaining about the same, and after ten minutes the feathers were removed, rinsed alkaline treatment of Trisodium phosphate is preferred because of its quicker action due to a higher pH. It is believed that Then the feathers were put in a bath tumble-dried,thetreated"feathers had a filling power of Basic chromic sulfate treatment 'Tliis' example; describes-a feather'treatrnenh'with; a basic chromic sulfate bath.- The basic chrornic sulfate used in this example is Tanolin R, which-isa' trade name for one-third basic chromic sulfate containing about 25% chromic oxide. Therecornmended procedure for employing this tanning agent for the treatment of feathers'in the bath for ten minutes longer, with occasional" stirring, at 44 Then-rinse'thoroughly' and tumble dry at'about 43 C. (black bulb temperature) the temperature rising to 1l0 C. when the feathers" are dry. The'filling power is 6.0 cm.

Another procedure giving about th'esame results is as follows; After the phosphate treatment, a '67 gram bath' e of chicken feathers. is well rinsed and then..put in1a 3.5%:bath of bromoacetic acid solution at pH 2.9, thetemperature being..42 C.E After.fifteen minutes,..the

pH of the solution is raised to.:9.5 and the'.:fea thers are keptin the solution for about two hours at 4l47 C.

. 4 hydrazine, and a mixture of hydrazine sulfate and spent chromic acid, the total" time of immersion of said feathers being sufficient. to increase substantially the filling power of said feathers, then removing said feathers and rinsing and drying them.

2. The method. according to claim 1, wherein said aqueous alkaline 'solutio'n-is-an'approximately 1% solutionof trisodium .zphosphate' having a temperature of about 43-49 C., said soaking having a duration of about 10-30 'minutes: I

' 3. A method oftreatingland fowl' feathers to enhance their filling power, which comprises modifying the cystine linkage of the .keratinyof said land fowl feathers by soaking said feathers in an aqueous.;alkaline solution until their curliness is increased,, rinsing said feathers, then placing said feathers in about 5% bromoacetic acid aqueous solution neutralized to about pH 7, then after about fifteen minutes raisingthe pH to about 9-9.5,

the'feathers'being keptin the-bathf'fo'r about 4 hours at about 48.-'5l' C.; then-rinsing the-feathersland placing .themin anaqueous'chrornic acid bath for about 2 /2 hours at about 34'--.44 C. and a pH of about '25- 2.7.;1then transferringr the feathers-to an about 0.1%

hydrazine"aqtieoussolutiomand keeping-them in said solution for-about one hour at'about 37-31 C.; then raising the-pH to'about =7, removing said feathers from thej'bath after their filling-power has been substantially I increased, then rinsing and drying them.

Then .the feathers are rinsed again and treated for three hours .with basic chromic. sulfate (e.'g;, Tanolin R at 42 -46 0., the pH being 4.1-3.8. Finally, the. .pH of :14. A'method of. treating land fowl-feathers to enhance theirfilling power, which comprises modifying the cys tine linkage-of the keratin of said land fowl feathers by the solutionisraisedto 6.4, and thefeathers are kept in the sludge for fifteen minutes longer. Finally, the

feathersare rinsed for twenty minutes, dried, and relaxed.

' A batch of 67 grams of chicken feathers was given the phosphate treatment already described, then the feathers were carefully rinsed. The dampfeathers were put in a chromic'acid bath (1500 ml. of 1% sodium bichromate solution or 0.8% chromic acid) for-two and one-half hoursat 39-43 C. and pH 28.5-2.7. Then fthefeathers were put in a hydrazine bath' (6 g.'of hydrazinesulfate plus 1300 ml. of water-plus 200 ml. of sp'enttchromic acid solution) and kept there for thirty minutes at' 37- 43 C., the pH being-3.94.0. Then the pH'was' raised to. 7.1 and the feathers were kept in the sludge-forten minutes longer. After this, they were rinsed, dried," and. relaxed. The filling power was 6.3 cm. After laundering," drying and relaxing, the filling power rose to 6.6'cm. Evidently the two-bath. chrome treatment. caused. more deep-seated and permanent changes in the feathers. than the one-bath treatment previously described.

Obviously the invention is. not limited'to thedetails. describedin the foregoing,;but is defined inthe appended claims. V

What we claim is:

hance' their. fillingipower, which comprises modifying the cystine linkage of the keratin of said land fowl feath-. ers by soaking said feathers inanaqueous alkaline-solution until their curliness is increased, rinsing said feathe solvedchromium compound is a basic chromic sulfate;

a basic. chromic their curliness isincreased, rinsingsaid feathers, then Q putting the land fowl 'feathersin an about.1.5 aqueous then continuing the immersion of: said feathersin an aqueous bath having a pH of about 6-7, said aqueous bathcontaining dissolved'therein a memberof the group. f

consisting. of chromic acid, a basic. chromicsulfate.

' drying them. I V

6. Amethqdoftreating land fowl feathers to enhance soaking said'feathers'in'an aqueous alkaline solution until their curliness is increased, rinsing 1 said feathers, then placing fthedand "fowl 'feathrsinjan about'2.4% chloro: acetic acid-solution for-about 20 minutes at a'pH of abouty2-.9 and =about42 "C.; then raising the pH to about 9.2-9.4 and-keeping. the feathers in' the alkaline bath at about 4l""-47"- C; for about 2 hours; then rinsing the feathers; then putting the feathers 'in a chromic acid bath madefromabout l5 -g.- sodiurnbichromate-in about 1500rnl.-of waterand "about 2 ml. of concentrated suling=;said feathers in an aqueous alkalinesolution until their; curliness-is'increased, rinsing said feathers, then placing "the" land fo'wl feathers in an ab out'j0.8%- chromic acid aqueous solution for about 2% hours at about 39- 43 ""C. and-a pHf'of about 2:5-2.7; then putting the feathers in an aqueous *liydr'azine' bath in'the presence of spent chromic acid dissolved in saidbath; keeping the.

fe'athersinsaidibathat about 37- 43 C. for about 1- A method of treating land. fowl feathersyt thirty minutes,"the fl beingabout 3.9 10 4.0, then-raising the'pH toabout 7 and keeping the feathers in'ythe sub-. stantiajlly neutral solutionfonabout. 10 minutes, then removing the; feathers. from. said solution and rinsing and' their filling power, which'eoinprises modifying the cystine linkage of the keratinof'saidlandfowl feathers by soakingisa'id feathers. in; an aqueous alkaline solution until solution. of...abasic .cbromicsulfate. at a pH. of about 3.5-3.8]and atemperature of..43-46 C. for about 170 ininutes,.then. raisingthe pH. to about 6.0 and keeping the feathers in the'bath at about 44 C. for about ten additional. minutes, then rinsing and drying them.

7'.: A methodpfntreatingdand fowlfeathers .to. enhance their filling power, which comprises modifying the cystine linkage of the keratin of said land fowl feathers by soakin; said feathers in an aqueous alkaline solution until their curliness is increased, rinsing said feathers, then placing said feathers in an about 3.5% bromoacetic acid aqueous solution at a pH of about 2.9, then after about 15 minutes raising the pH to about 9.5, keeping said feathers in said solution for about 2 hours at about 41-47 C.; then rinsing the feathers and placing them in an aqueous solution of a basic chromic sulfate at a pH of about 3.8-4.1 and a temperature of about 42-46 C. for about 3 hours, then raising the pH to about 6.4 and keeping the feathers in said chromic acid solution for about 15 additional minutes, then rinsing said feathers and drying them.

8. The product produced by the method of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Speakman: Iour. of the Soc. of Dyers and Colourists, September 1936, pp. 335-346.

Speakman: Jour. of the Soc. of Dyers and Colourists, June 1937, pp. 236-242. 

1. A METHOD OF TREATING LAND FOWL FEATHERS TO ENHANCE THEIR FILLING POWER, WHICH COMPRISES MODIFYING THE CYSTING LINKAGE OF THE KERATIN OF SAID LAND FOWL FEATHERS BY SOAKING SAID FEATHERS IN AN AQUEOUS ALKALINE SOLUTION UNTIL THEIR CURLINESS IS INCREASED, RINSING SAID FEATHERS, THEN PLACING SAID LAND FOWL FEATHERS FOR AT LEAST ABOUT 2 HOURS IN AN AQUEOUS BATH CONTAINING DISSOLVED THEREIN A CHROMIUM COMPOUND BEING A MEMBER OF THE GROUP CONSISTING OF CHROMIC ACID AND A BASIC CHROMIC SULFATE AT ABOUT 34*-46* C., THE INITIAL PH OF SAID BATH BEING ABOUT 2.5-2.7 WHEN SAID DISSOLVED CHROMIUM COM POUND IS CHROMIC ACID AND ABOUT 3.5-4.1 WHEN SAID DISSOLVED CHROMIUM COMPOUND IS BASIC CHROMIC SULFATE, THEN CONTINUING THE IMMERSION OF SAID FEATHERS IN AN AQUEOUS BATH HAVING A PH OF ABOUT 6-7, SAID AQUEOUS BATH CONTAINING DISSOLVED THEREIN A MEMBER OF THE GROUP CONSISTING OF CHROMIC ACID, A BASIC CHROMIC SULFATE, HYDRAZINE, AND MIXTURE OF HYDRAZINE SULFATE AND SPENT CHROMIC ACID, THE TOTAL TIME OF IMMERSION OF SAID FEATHERS BEING SUFFICIENT TO INCREASE SUBSTANTIALLY THE FILLING POWER OF SAID FEATHERS, THEN REMOVING SAID FEATHERS AND RINSING AND DRYING THEM. 